This invention relates generally to a pump and motor assembly and more specifically to the manner in which a motor armature is accurately aligned with a cam or stator ring of a pump.
A known pump and motor assembly is disclosed in U.S. patent application Ser. No. 748,061 filed Dec. 6, 1976 by Drutchas et al. and entitled "Pump and Motor Assembly". The pump and motor assembly disclosed in this application includes an electric motor having an armature shaft. One end of the armature shaft is rotatably supported by a bearing which is mounted in a dividing wall between pump and motor sections of a common housing. A cheek plate of the pump unit is supported in coaxial relationship with the motor armature by mounting the cheek plate on the same bearing as is utilized to support the motor armature shaft. An anchor pin engages the dividing wall to hold the cheek plate against the rotation. Dowel pins which are separate from the anchor pin, extend outwardly from the opposite side of the inner cheek plate to support the cam ring of the pump unit. Problems may be encountered with this construction due to a build-up of tolerances between the various reference surfaces for positioning the motor armature shaft and pump cam ring.